title: Growth of human bronchial epithelial cells at an air-liquid interface alters the response to particle exposure.
abstract: BACKGROUND
  We tested the hypothesis that normal human bronchial epithelial (NHBE) cells 1) grown submerged in media and 2) allowed to differentiate at air-liquid interface (ALI) demonstrate disparities in the response to particle exposure.
  
  
  RESULTS
  Following exposure of submerged NHBE cells to ambient air pollution particle collected in Chapel Hill, NC, RNA for IL-8, IL-6, heme oxygenase 1 (HOX1) and cyclooxygenase 2 (COX2) increased. The same cells allowed to differentiate over 3, 10, and 21 days at ALI demonstrated no such changes following particle exposure. Similarly, BEAS-2B cells grown submerged in media demonstrated a significant increase in IL-8 and HOX1 RNA after exposure to NIST 1648 particle relative to the same cells exposed after growth at ALI. Subsequently, it was not possible to attribute the observed decreases in the response of NHBE cells to differentiation alone since BEAS-2B cells, which do not differentiate, showed similar changes when grown at ALI. With no exposure to particles, differentiation of NHBE cells at ALI over 3 to 21 days demonstrated significant decrements in baseline levels of RNA for the same proteins (i.e. IL-8, IL-6, HOX1, and COX2). With no exposure to particles, BEAS-2B cells grown at ALI showed comparable changes in RNA for IL-8 and HOX1. After the same particle exposure, NHBE cells grown at ALI on a transwell in 95% N2-5% CO2 and exposed to NIST 1648 particle demonstrated significantly greater changes in IL-8 and HOX1 relative to cells grown in 95% air-5% CO2.
  
  
  CONCLUSIONS
  We conclude that growth of NHBE cells at ALI is associated with a diminished biological effect following particle exposure relative to cells submerged in media. This decreased response showed an association with increased oxygen availability.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Ghio
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Dailey
authors.forename: Joleen M
authors.initials: JM
authors.lastname: Soukup
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Stonehuerner
authors.forename: Judy H
authors.initials: JH
authors.lastname: Richards
authors.forename: Robert B
authors.initials: RB
authors.lastname: Devlin
mesh_terms: D001980:Bronchi / Q000187:drug effects* / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D015687:Cell Hypoxia; D002460:Cell Line; D049109:Cell Proliferation; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation; D051547:Heme Oxygenase-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D052638:Particulate Matter / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors
chemical_list: C508606:CXCL8 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D052638:Particulate Matter; D012333:RNA, Messenger; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D010100:Oxygen